/*
TASK:minitime
LANG:C++
*/
# include <iostream>
using namespace std;
int main ()
{
    int n,b,max;
    cin>>n;
    max=n;
    for (int i=2;i<=max;i++)
    {
        if(n/i==0)
              b=n/i;
        else
              b=n/i+1;
        b=b+i;
        if (max>b)
             max=b;
    }
    cout<<max<<endl;  
}
